One vertex per element, one color per generator, with an edge from x to x·s.
(2,3)(5,6)(7,11)(8,9)(10,12)(14,19)(15,23)(16,17)(20,22)(21,28)(24,25) involution — undirected(1,2,4,3)(5,6)(7,10)(8,9)(11,12)(14,20)(15,24)(16,17)(19,22)(21,28)(23,25)(6,9)(10,11)(13,14,16,19,18,22,17,20)(15,21,23,26,25,28,24,27)(5,7,8,12)(6,10,9,11)(13,15,16,23,18,25,17,24)(14,21,19,26,22,28,20,27)(1,3,4,2)(15,25)(21,28)(23,24)(26,27)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.